Method of using interventional medical device system having an elongation retarding portion

ABSTRACT

Use of an interventional medical device system operable while within a body vessel is provided with a generally hollow tubular proximal portion, distal portion, and intermediate portion. The proximal portion and at least part of the distal portion remains outside of the body in use, with the remainder of the distal portion positioned within the body. The intermediate portion includes a spiral ribbon having adjacent turns, with at least one frangible bridge member between two adjacent turns. The proximal and distal portions are movable away from each other by elongating the spiral ribbon and, eventually, breaking the frangible bridge member. According to the method of using such a system to deploy an implantable medical device, such as an embolic coil, an actuation member is moved proximally with the proximal portion to disengage a bond or joint between the actuation member and the implantable medical device.

This is a divisional of U.S. patent application Ser. No. 011/461,231,filed Jul. 31, 2006, hereby incorporated by reference hereinto.

FIELD OF THE INVENTION

This invention generally relates to interventional medical devicesystems that are navigable through body vessels of a human subject. Moreparticularly, this invention relates to tubular devices having afrangible elongation retarding feature and methods of using the same.

DESCRIPTION OF RELATED ART

The use of catheter delivery systems for positioning and deployingtherapeutic devices, such as dilation balloons, stents and emboliccoils, in the vasculature of the human body has become a standardprocedure for treating vascular diseases. It has been found that suchdevices are particularly useful in treating areas where traditionaloperational procedures are impossible or pose a great risk to thepatient, for example in the treatment of intracranial aneurysms. Due tothe delicate tissue surrounding intracranial blood vessels, especiallyfor example brain tissue, it is very difficult and often risky toperform surgical procedures to treat defects of the intracranial bloodvessels. Advancements in catheter deployment systems have provided analternative treatment in such cases. Some of the advantages of catheterdelivery systems are that they provide methods for treating bloodvessels by an approach that has been found to reduce the risk of traumato the surrounding tissue, and they also allow for treatment of bloodvessels that in the past would have been considered inoperable.

Typically, these procedures involve inserting the distal end of adelivery catheter into the vasculature of a patient and guiding itthrough the vasculature to a predetermined delivery site. A vascularocclusion device, such as an embolic coil, is attached to the end of adelivery member which pushes the coil through the catheter and out ofthe distal end of the catheter into the delivery site. Some of theproblems that have been associated with these procedures relate to theaccuracy of coil placement. For example, the coil detachment mechanismmay cause the embolic coil to partially or fully dislodge from thepredetermined site or dislodge previously deployed coils.

In response to accuracy concerns, numerous devices and releasemechanisms have been developed in an attempt to provide a deploymentsystem which allows control of the occlusion device after the device hasbeen delivered by the catheter and to also provide a rapid release ordetachment mechanism to release the device once it is in place. One suchdevice is disclosed in Geremia et al. U.S. Pat. No. 5,108,407, whichshows a fiber optic cable including a connector device mounted to theend to the optic fiber. An embolic coil is attached to the connectordevice by a heat releasable adhesive. Laser light is transmitted throughthe fiber optic cable to increase the temperature of the connectordevice, which melts the adhesive and releases the embolic coil. Onedrawback to using this type of system is the potential risk of meltedadhesives contaminating the blood stream.

Another coil deployment system employs a pusher member having an emboliccoil attached to the pusher member by a connector fiber which is capableof being broken by heat, as disclosed in Gandhi et al. U.S. Pat. No.6,478,773. The pusher member of this arrangement includes an electricalresistance heating coil through which the connector fiber is passed.Electrical current is supplied to the heating coil by a power sourceconnected to the heating coil via wires extending through an internallumen of the pusher. The power source is activated to increase thetemperature of the heating coil which breaks the connector fiber. Onedrawback is that connecting the resistance heating coil to the powersource requires running multiple wires through the pusher member.Additionally, the electrical current traveling through the wires maycreate stray electromagnetic fields that have the potential to interferewith other surgical and monitoring equipment.

Yet another embolic coil positioning and delivery system is described inSaadat et al. U.S. Pat. No. 5,989,242, which discloses a catheter havinga shape memory alloy connector attached to the distal end of thecatheter. The connector includes a socket having a pair of spaced-apartfingers which are responsive to a change in temperature. The fingers arebent towards each other and hold a ball which is connected to an end ofan embolic coil. The connector absorbs laser light transmitted throughan optical cable and transforms the light into heat energy. The heatenergy raises the temperature of the connector and opens the fingers,thereby releasing the embolic coil. This type of ball and socketconnection is rigid and causes the catheter to be stiff, making itdifficult to guide the catheter through the vasculature of the body.This patent, and all other patents and references identified herein arehereby incorporated herein by reference.

Further, the above-identified delivery systems typically requireelectronic equipment powered by a power source. If the electronicequipment is defective or the power source fails, the procedure may beprolonged while the equipment is repaired or replaced. Prolonging theprocedure may expose the patient to additional risk.

Even among delivery systems not requiring electronic equipment, a commonfeature is the need for a separate handle component, such as anattachable handle, a peelable sheath system, a syringe, that ismanipulated by the medical professional to release the implantabledevice. Attachable handle components often require the use of additionalcomponents, such as a re-zip sheath, for proper operation including asan introducer component. This tends to increase the time and complexityof releasing the implantable device, as well as increasing the componentand packaging costs.

Therefore, a need remains for a rapid release vascular occlusiondeployment system or method that can function without electricalequipment or a power supply, does not develop chemical debris, is simpleto manufacture, flexible and easy to guide through the vasculature ofthe body, provides excellent control over the occlusion device, andreduces the possibility of interference with other surgical and/ormonitoring equipment. Further advantages could be realized with a handlesystem that has a low profile such as having the same outer diameterdimension as the overall delivery system.

SUMMARY OF THE INVENTION

In accordance with one embodiment or aspect of the present invention, aninterventional medical device system operable while within a body vesselis provided with a generally hollow tubular proximal portion, distalportion, and intermediate portion. The proximal portion remains outsideof the body in use, while at least a portion of the distal portion ispositioned within the body during use. The intermediate portion, whichtypically remains outside of the body during use of the system, includesa spiral ribbon having adjacent turns, with at least one frangiblebridge member between two adjacent turns. The proximal and distalportions are movable away from each other by elongating the spiralribbon and, eventually, breaking the frangible bridge member.

According to another embodiment or aspect of the present invention, aninterventional medical device system operable while within a body vesselis provided with a proximal portion handle, a distal portion, and anintermediate portion. At least a portion of the distal portion ispositioned within the body during use. The intermediate portion includesa proximal helical section adjacent to the proximal handle portion, adistal helical section adjacent to the distal portion, and anintermediate helical section between the other two helical sections. Theintermediate helical section includes a plurality of adjacent turns,with a frangible bridge member between two adjacent turns. The proximaland distal portions are movable away from each other by elongating theintermediate portion and, eventually, breaking the frangible bridgemember.

To incorporate systems according to the preceding description into animplant delivery device, an actuation member is connected to theproximal portion, and an implantable medical device is associated with adeployment end of the actuation member. Movement of the proximal portionof the system away from the distal portion disengages the implantabledevice at a target location within the vasculature. The bridge memberretards axial extension of the turns for improved control when releasingthe implantable device.

According to yet another embodiment or aspect the present invention, amethod of using an interventional medical device system in a body vesselincludes providing a generally hollow tubular system. The tubular systemincludes a distal end portion, a proximal end handle portion, anintermediate portion, and an actuation member. The intermediate portioncomprises a spiral having a plurality of turns and at least one bridgemember between two adjacent turns. The actuation member is fixedlyconnected to the proximal end handle portion and extends to the distalend portion of the system. At least a portion of the distal end portionof the system is introduced into a body vessel and positioned generallyadjacent to a target location within the vessel. The proximal end handleportion is then moved proximally with respect to the distal end portion,thereby breaking the bridge member and proximally moving the actuationmember. If provided, an implantable medical device associated with adeployment end portion of the actuation member is released into thetarget location upon proximal movement of the actuation member.

Special application for the present invention has been found for tubularportions of embolic coil/implant detachment systems. However, thepresent invention is also applicable to tubular components of otherdevices adapted for movement through body lumens and requiringcontrolled elongation of the device, so it will be understood that theproducts and methods described herein are not limited to particularmedical devices or particular surgical applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a medical device portion accordingto an aspect of the present invention, in a pre-actuation condition;

FIG. 2 is a front elevational view of the medical device portion of FIG.1, in a post-actuation condition;

FIG. 3 is a detail view of an intermediate helical section of themedical device portion of FIG. 1; and

FIG. 4 is a detail view of a proximal helical section of the medicaldevice portion of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention in virtually any appropriate manner.

FIGS. 1 and 2 illustrate a generally hollow or tubular structureaccording to the present invention. When used herein, the terms“tubular” and “tube” are to be construed broadly and are not limited toa structure that is a right cylinder or strictly circumferential incross-section or of a uniform cross-section throughout its length. Forexample, the tubular device or system is generally designated at 10 andshown as a substantially right cylindrical structure. However, thetubular system may have a tapered or curved outer surface withoutdeparting from the scope of the present invention. As an illustrationand as described in greater detail herein, a proximal portion 12 of thesystem 10 may be used as a handle to manipulate the system 10, so it maybe relatively large, tapered, and/or otherwise shaped for improvedgripping without departing from the scope of the present invention.

The system 10 is comprised of a generally hollow tubular proximalportion or proximal portion handle or proximal end handle portion 12,distal portion or distal end portion 14, and intermediate portion 16.Preferably, the proximal and distal portions 12 and 14 are substantiallynon-compressible, non-elongatable metal hypotubes or portions of thesame single hypotube. The intermediate portion 16 includes a pluralityof spiral turns 18 and is elongatable, as illustrated in FIGS. 1 and 2.In a preferred embodiment, the system 10 is provided as an elongatedmetal hypotube, with the intermediate portion 16 comprising a spiral-cutportion thereof. The structure of the intermediate portion 16 isdescribed in greater detail herein.

The proximal portion 12 remains outside of the body during use and maybe used as a handle of the system 10 to be gripped and manipulated by auser. The proximal portion 12 may include a plug member 20 fixedlyconnected to an anchored end 22 of an elongated actuation member 24,which actuation member 24 extends at least from an interior lumen of theproximal portion 12 to an interior lumen of the distal portion 14. Theactuation member 24 may be comprised of a metal or polymer and formed asa wire, tube, or other elongated structure. The anchored end 22 may beconnected to the plug member 20 by any suitable means, including (butnot limited to) adhesive, metallic bonding, and heat fusing. Thefunction of the actuation member 24 is described in greater detailherein.

The distal portion 14 of the system 10 is adapted to be received by abody vessel. It will be appreciated that only a small section of thedistal portion 14 is illustrated in FIGS. 1 and 2, as the distal portion14 is preferably relatively lengthy with respect to the proximal portion12, so that it can extend through the vasculature to reach a targetlocation. For example, in one embodiment, the system 10 has a length inthe range of approximately 180 and 200 cm, with the proximal portion 12and the intermediate portion 16 collectively accounting forapproximately 15 cm of the total length. Preferably, only a portion ofthe distal portion 14 is received within the body during use, with theremainder being positioned outside of the body to be manipulated by auser, as will be described in greater detail herein. If provided, theactuation member 24 extends into an interior lumen of the distal portion14, with a deployment end (not illustrated) of the actuation member 24adjacent to or extending beyond the end of the distal portion 14.

The proximal and distal portions 12 and 14 are separated by theintermediate portion 16, which preferably remains outside of the bodyduring use. Sections of a preferred intermediate portion 16 are shown ingreater detail in FIGS. 3 and 4. The intermediate portion 16 includes atleast an interrupted spiral section 26 (FIG. 3), also referred to hereinas an intermediate helical section. The intermediate helical section 26comprises a spiral ribbon 28 having adjacent turns 18, similar to atypical wound wire or spiral-cut tube. However, while the turns of atypical wound wire or spiral-cut tube are defined and separated by acontinuous helical opening, the turns 18 of the intermediate helicalsection 26 are separated by an interrupted spiral 30. The interruptedspiral is characterized by an open or cut section 32 and at least oneuncut section or frangible bridge member 34 between two adjacent turns18. Preferably, the intermediate helical section 26 includes a pluralityof alternating cut and uncut sections 32 and 34. The alternating cut anduncut sections 32 and 34 preferably define a single substantiallyhelical pattern, which may simplify manufacture of the intermediatehelical section 26.

Each bridge member 34 may be formed according to the teachings of anapplication entitled “Interventional Medical Device Component Having AnInterrupted Spiral Section And Method Of Making The Same” (AttorneyDocket No. 0805-0355), filed herewith on Jul. 31, 2006, which is herebyincorporated herein by reference. This application also provides detailsof bridge member distribution that may be suitable for some embodimentsof the present disclosure. Briefly, the intermediate helical section 26may be formed by spiral-cutting a portion of a hypotube. The cuttingmember is deactivated at selected intervals, while still moving in ahelical path with respect to the hypotube, in order to create frangiblebridge members 34. Alternatively, the intermediate helical section 26may be provided as a wound wire, with welds between adjacent turns ofthe wire serving as frangible bridge members 34. In the presentdisclosure, the bridge members typically are designed to be frangible asdiscussed herein. Other methods of manufacturing the intermediatehelical section 26 may also be practiced without departing from thescope of the present invention.

Preferably, each frangible bridge member is out of axial alignment withany and each frangible bridge member immediately adjacent thereto. Forexample, FIG. 3 illustrates an exemplary bridge member 34 a out of axialalignment with the adjacent bridge members 34 b, 34 c. Rather than beingaxially aligned, the bridge members 34 of FIG. 3 are arranged in agenerally helical pattern “H”, which provides an advantageousdistribution that promotes substantially uniform performancecharacteristics (e.g., flexibility, rigidity, and stretch resistance)along the intermediate helical section 26. A regular, non-axiallyaligned distribution may also be preferred to prevent preferentialbending of the intermediate helical section 26 before or after thefrangible bridge members 34 are broken.

The intermediate portion 16 is axially elongatable from a pre-actuationcondition (FIG. 1) to a post-actuation condition (FIG. 2) by proximallymoving the proximal portion 16 away from the distal portion 14. Thetotal elongation length is represented in FIG. 1 at “D”. The presence ofthe frangible bridge members 34 makes the system 10 more stretchresistant than a typical wound ribbon or spiral cut tube, so theelongation of the intermediate portion 16 is more controlled.

Each frangible bridge member 34 preferably is adapted to break after theturns 18 of the intermediate helical section 26 begin to elongate, butbefore the post-actuation condition of FIG. 2. As an elongatablestructure, the intermediate helical section 26 will begin to elongate,at least nominally, when subjected to any longitudinally directedtensile force, but the frangible bridge members 34 may be adapted tobreak at a greater threshold pull force. For example, in neurovascularapplications, the frangible bridges may be adapted to break at a pullforce in the range of approximately 0.2 and 0.6 lbf, preferably at apull force of approximately 0.4 lbf. Of course, other threshold pullforces may be used, and may even be preferred for applications outsideof the neurovasculature.

Preferably, the minimum breaking force is greater than the forcerequired to withdraw the system 10 from the vasculature; otherwise thebridge member or members 34 may break during repositioning or removal ofthe system. The required breaking force of the bridge member 34 isdetermined by a number of factors and can be calibrated to break at apre-selected pull force by adjusting the number, width, thickness,arcuate extent, and/or constituent material of the bridge members 34.Furthermore, when a plurality of bridge members 34 are provided, theyneed not be identical, but can be differently configured from each otherto allow, for example, breaking and elongation at different pull forcesand in stages.

In the embodiment of FIGS. 1 and 2, the intermediate helical section 26is bracketed by a proximal helical section 36 and a distal helicalsection 38. The illustrated proximal helical section 36 is shown ingreater detail in FIG. 4, with the distal helical section 38 preferablybeing a mirror image thereof. As shown in FIG. 4, the proximal anddistal helical sections 36 and 38 are preferably comprised of aplurality of turns 40 of a typical wound wire or spiral-cut tube, theturns 40 being defined and separated by a continuous helical opening 42.If one or both are provided, the proximal and distal helical sections 36and 38 each act as a transition or buffer between the interrupted spiralsection 26 and the proximal and distal portions 12 and 14 of the system10. If the interrupted spiral 30 is positioned adjacent to thesubstantially tubular proximal and/or distal portions 12 and 14, thenthere is a risk that large stress concentrations can develop at theinterfaces between the intermediate helical section 26 and the uncutproximal and distal portions 12 and 14, which may lead to fracture ofthe system 10 at the interfaces. The presence of the proximal and/ordistal helical sections 36 and 38 reduces this risk.

The width of an exemplary turn of the proximal helical section 36 isdesignated in FIG. 4 as “W”, while the width of an exemplary turn of theintermediate helical section 26 is designated in FIGS. 3 and 4 as “ω”.In a preferred embodiment, the width “W” of at least one turn 40 of oneof the proximal and distal helical sections 36 and 38 is greater thanthe width “ω” of at least one turn 18 of the intermediate helicalsection 26. This provides a smoother transition between the intermediatehelical section 26 and the proximal and/or distal portions 12 and 14 ofthe system 10, compared to a configuration wherein the turns 40 of theproximal and distal helical sections 36 and 38 have an equal or smallerwidth than the turns 18 of the intermediate helical section 26. In apreferred embodiment, the turns 40 of the proximal and distal helicalsections 36 and 38 are substantially identical to each other, the turns18 of the intermediate helical section 26 are identical to each other,and the width “W” of the turns 40 of the proximal and distal helicalsections 36 and 38 is greater than the width “ω” of the turns 18 of theintermediate helical section 26.

It is further contemplated that, instead of or in addition to providingthe turns 40 of the proximal and distal helical sections 36 and 38 withincreased widths W, the turns 40 may be provided with frangible ornon-frangible bridge members (not illustrated) between adjacent turns40. In particular, an interrupted spiral according to the foregoingdescription is created, with the bridge members of the proximal anddistal helical sections 36 and 38 being wider and stronger than thefrangible bridge members 34 of the intermediate helical section 26, suchthat they do not break during normal use or only break after thefrangible bridge members 34 of the intermediate helical section 26. Aswith the frangible bridge members 34 of the intermediate helical section26, it may be preferred for bridge members of the proximal and/or distalhelical sections to be arranged in a regular, non axially aligneddistribution to avoid creating a bending preference.

Special application for systems according to the present invention hasbeen found in delivery devices for releasing implantable medicaldevices, such as embolic coils, to a target location of a body vessel.For such devices, an implant is operatively connected to a deploymentend of the actuation member 24. The implant is initially positionedadjacent to the end of the distal end portion 14 of the system 10, andconnected and oriented such that proximal movement of the actuationmember 24 with respect to the distal end portion 14 will release theimplant. This may be accomplished in any of a number of ways, such as bypositioning the implant in abutment with the end of the distal endportion 14, in which case proximal relative movement of the actuationmember 24 will cause the implant to bear against the distal end portion14, thereby disengaging a connection such as a bond or joint between theactuation member 24 and the implant and releasing the implant.

In use, part of the distal end portion 14 of the system 10 is insertedinto a body vessel in the pre-actuation condition of FIG. 1. Ifpreferred, the distal end portion 14 may be delivered in a separateintroducer or catheter, or can be fed through a catheter already placedwithin the vessel. The distal end portion 14 is positioned adjacent to atarget location of the body vessel and held in place. The proximal endhandle portion 12 and the intermediate portion 16 remain outside of thebody, along with part of the distal end portion 14. The proximal endhandle portion 12 is moved proximally with respect to the distal endportion 14, causing the intermediate portion 16 to begin to elongate bystretching the turns 18. Thereafter, the intermediate portion 16continues to elongate by either stretching the turns 40 (if provided) orbreaking a frangible bridge member 34, the order of elongation dependingon the relative strengths of the frangible bridge member or members 34and (if provided) the turns 40 of the proximal and distal helicalsections 36 and 38.

Elongating the intermediate portion 16 thusly also causes the actuationmember 24, which is fixed to the proximal end handle portion 12, to moveproximally. Eventually, when sufficient pull force has been applied tothe proximal end handle portion 12, the frangible bridge members 34 willbreak and the intermediate portion 16 will elongate into thepost-actuation condition of FIG. 2. If the proximal and distal helicalsections 36 and 38 are also provided with frangible bridge members, thensufficient force must be provided to break all of the bridge members ofthe intermediate section 16 before the system 10 achieves thepost-actuation condition. In the post-actuation condition, the actuationmember 24 has been moved proximally to such a degree that the implant(not shown) is released from the deployment end into the target locationof the body vessel. Deployment end and implant details for a particularembodiment suitable for use with the present handle arrangement arefound in an application entitled “Implantable Medical Device DetachmentSystem and Methods of Using the Same” (Attorney Docket No. 0805-0357),filed herewith on Jul. 31, 2006, which is hereby incorporated herein byreference.

By a preferred safety mechanism, the system 10 may be adapted such thatthe actuation member 24 will not release the implantable medical deviceuntil the frangible bridge members 34 break. This may be achieved, forexample, by preventing release of the implant until a pre-selectedactuation member displacement “D” (FIG. 1) that can only be achievedwhen the frangible bridge members 34 have been broken. At a pull forcebelow the breaking force, the actuation member 24 is only partiallyretracted, so the implant remains connected to the actuation member 24and the system 10 may be repositioned before deploying the implant.

It will be seen from the preceding description that delivery devicesincorporating systems according to the present invention eliminatenumerous problems associated with known devices. In particular, no powersource is required to release the implant, so the system is lessvulnerable to power outages. Furthermore, a separate handle member isnot required, because one is inherent in the system, which decreasescosts, complexity, and the time needed to release an implant.

It will be understood that the embodiments of the present inventionwhich have been described are illustrative of some of the applicationsof the principles of the present invention. Numerous modifications maybe made by those skilled in the art without departing from the truespirit and scope of the invention, including those combinations offeatures that are individually disclosed or claimed herein.

1. A method of using an interventional medical device system in a bodyvessel, comprising: providing a generally hollow tubular systemcomprising: (a) a distal end portion, (b) a proximal end handle portion,(c) an intermediate portion between the distal end portion and theproximal end handle portion, said intermediate portion comprising aspiral having a plurality of turns and at least one bridge memberbetween two adjacent turns, and (d) an actuation member fixedlyconnected to the proximal end handle portion and extending generallyfrom an interior of the proximal end handle portion of the system to aninterior of the distal end portion of the system; introducing a portionof the distal end portion of the system into a body vessel; positioningthe distal end portion of the system generally adjacent to a targetlocation within the body vessel; moving the proximal end handle portionproximally with respect to the distal end portion; and thereby breakingthe bridge member and proximally moving the actuation member.
 2. Themethod of claim 1, wherein said moving of the proximal end handleportion, said breaking of the bridge member, and said proximal moving ofthe actuation member comprise the same proximal movement of the proximalend handle portion of the system.
 3. The method of claim 1, wherein saidproviding of a generally hollow tubular delivery system includesproviding an intermediate portion comprising a plurality of the bridgemembers, and wherein said breaking the bridge member includes breakingsaid plurality of bridge members.
 4. The method of claim 1, wherein saidproviding of a generally hollow tubular delivery system includesproviding the intermediate portion with a proximal helical sectionadjacent to the proximal end handle portion, a distal helical sectionadjacent to the distal end portion of the system, and an intermediatehelical section substantially defined by the intermediate helicalsection turns and the bridge member, and wherein said moving of theproximal end handle portion includes elongating the proximal helicalsection and the distal helical section.
 5. The method of claim 1,further including providing an implantable medical device andoperatively connecting same to a deployment end portion of the actuationmember, wherein said moving of the proximal end handle portion whichproximally moves the actuation member also disengages the implantablemedical device from the actuation member and delivers the implantablemedical device for implanting same within the body vessel.
 6. The methodof claim 1, wherein said providing of a generally hollow tubulardelivery system includes providing the intermediate portion with (a) aproximal helical section adjacent to the proximal end handle portion anddefined by a plurality of turns, (b) a distal helical section adjacentto the distal end portion of the system and defined by a plurality ofturns, (c) an intermediate helical section substantially defined by theintermediate helical section turns and the bridge member, and (d) atleast one bridge member between two adjacent turns of one of theproximal helical section and the distal helical section and adapted tobreak after the bridge member of the intermediate helical section; andwherein said moving of the proximal end handle portion includes breakingthe bridge member of the proximal helical section or the distal helicalsection.
 7. A method of using an interventional medical device system ina body vessel, comprising: providing a generally hollow tubular systemcomprising: (a) a distal end portion, (b) a proximal end handle portion,(c) an intermediate portion between the distal end portion and theproximal end handle portion, said intermediate portion comprising aspiral-cut section of a hypotube having a plurality of turns and with aninterrupted spiral-cut section having a plurality of frangible bridgemembers between two adjacent turns, and (d) an actuation member fixedlyconnected to the proximal end handle portion and extending generallyfrom an interior of the proximal end handle portion of the system to aninterior of the distal end portion of the system; said providing furtherincluding providing bridge members out of axial alignment with a bridgemember immediately adjacent thereto; introducing a portion of the distalend portion of the system into a body vessel; positioning the distal endportion of the system generally adjacent to a target location within thebody vessel; moving the proximal end handle portion proximally withrespect to the distal end portion; and thereby breaking bridge membersand proximally moving the actuation member, and the bridge membersretard axial extension of the spiral ribbon thereat in response toapplication of a force applied to the intermediate portion from theproximal portion.
 8. The method of claim 7, wherein said moving of theproximal end handle portion, said breaking of the bridge member, andsaid proximal moving of the actuation member comprise the same proximalmovement of the proximal end handle portion of the system.
 9. The methodof claim 7, wherein said breaking the bridge member includes breakingsaid plurality of bridge members.
 10. The method of claim 7, whereinsaid providing of a generally hollow tubular delivery system includesproviding the intermediate portion with a proximal helical sectionadjacent to the proximal end handle portion, a distal helical sectionadjacent to the distal end portion of the system, and an intermediatehelical section substantially defined by the intermediate helicalsection turns and by the bridge members, and wherein said moving of theproximal end handle portion includes elongating the proximal helicalsection and the distal helical section.
 11. The method of claim 7,further including providing an implantable medical device andoperatively connecting same to a deployment end portion of the actuationmember, wherein said moving of the proximal end handle portion whichproximally moves the actuation member also disengages the implantablemedical device from the actuation member and delivers the implantablemedical device for implanting same within the body vessel.
 12. Themethod of claim 7, wherein said providing of a generally hollow tubulardelivery system includes providing the intermediate portion with (a) aproximal helical section adjacent to the proximal end handle portion anddefined by a plurality of turns, (b) a distal helical section adjacentto the distal end portion of the system and defined by a plurality ofturns, (c) an intermediate helical section substantially defined by theintermediate helical section turns and the bridge members, and (d) thebreaking includes breaking at least one bridge member between twoadjacent turns of one of the proximal helical section and the distalhelical section after breaking the bridge member of the intermediatehelical section; and wherein said moving of the proximal end handleportion includes breaking the bridge member of the proximal helicalsection or the distal helical section.
 13. The method of claim 7,further including fixedly connecting the actuation member to theproximal end handle and extending same through a passageway of theproximal end handle and through a passageway of the distal end portion.14. The method of claim 13, further including deploying an implantablemedical device by movement of the activation member at a location distalof the intermediate portion when the spiral ribbon axially elongatesbetween the proximal and distal portions.
 15. The method of claim 7,wherein said breaking occurs at a pre-selected pull force.